Method Detail

initialize

Initialize the sequencer. This is called automatically by ModeShape once for each Sequencer instance, and should not be
called by the sequencer.

By default this method does nothing, so it should be overridden by implementations to do a one-time initialization of any
internal components. For example, sequencers can use the supplied registry and nodeTypeManager
objects to register custom namesapces and node types required by the generated content.

execute

Execute the sequencing operation on the specified property, which has recently been created or changed.

Each sequencer is expected to process the value of the property, extract information from the value, and write a structured
representation (in the form of a node or a subgraph of nodes) using the supplied output node. Note that the output node
will either be:

the selected node, in which case the sequencer was configured to generate the output information directly under the
selected input node; or

a newly created node in a different location than node being sequenced (in this case, the primary type of the new node
will be 'nt:unstructured', but the sequencer can easily change that using Node.setPrimaryType(String))

The implementation is expected to always clean up all resources that it acquired, even in the case of exceptions.

Note: This method must be threadsafe: ModeShape will likely invoke this method concurrently in separate threads,
and the method should never modify the state or fields of the Sequencer implementation class. All initialization should be
performed in Sequencer.initialize(NamespaceRegistry, NodeTypeManager).

inputProperty - the property that was changed and that should be used as the input; never null

outputNode - the node that represents the output for the derived information; never null, and will either be
new if the output is being placed outside of the selected node, or will not be new when the
output is to be placed on the selected input node

context - the context in which this sequencer is executing, and which may contain additional parameters useful when
generating the output structure; never null

Returns:

true if the sequencer's output should be saved, or false otherwise

Throws:

Exception - if there was a problem with the sequencer that could not be handled. All exceptions will be logged
automatically as errors by ModeShape.